Driver, 40, who stars in new movie Barney's Version, admitted she found it funny to see a 'gorgeous' actress drunk and suffering a wardrobe malfunction at the event.
While in the bathroom at the party, she was with a 'very gorgeous, lovely, young actress coming out of the stall' with her underwear showing.
She added on The Ellen DeGeneres Show: 'I did stop and help her, and I said: 'I'm just glad you're wearing knickers.' But I don't think she knew what knickers were because it's an English word, but it was good.
'It was really good. It was a good story.'
Driver said she found it funny seeing a well-known actress looking less than perfect.
She said: 'It's kind of hilarious and daunting seeing your icons kind of hammered. Not necessarily fall down drunk - but definitely saying inappropriate things - and it's very lovely and it's sort of weird and awful, and I enjoy it.'